<?php //$Id: filter.php,v 1.20 2007/06/19 17:24:34 skodak Exp $

///////////////////////////////////////////////////////////////////////////
//																	   //
// This program is part of Moodle - Modular Object-Oriented Dynamic	  //
// Learning Environment - http://moodle.org							  //
//																	   //
// Copyright (C) 2004  Gaetan Frenoy <gaetan@frenoy.net>				 //
//					 Eloy Lafuente <stronk7@moodle.org>				//
//																	   //
// This program is free software; you can redistribute it and/or modify  //
// it under the terms of the GNU General Public License as published by  //
// the Free Software Foundation; either version 2 of the License, or	 //
// (at your option) any later version.								   //
//																	   //
// This program is distributed in the hope that it will be useful,	   //
// but WITHOUT ANY WARRANTY; without even the implied warranty of		//
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the		 //
// GNU General Public License for more details:						  //
//																	   //
//		  http://www.gnu.org/copyleft/gpl.html						 //
//																	   //
///////////////////////////////////////////////////////////////////////////

// Given XML multilinguage text, return relevant text according to
// current language:
//   - look for multilang blocks in the text.
//   - if there exists texts in the currently active language, print them.
//   - else, if there exists texts in the current parent language, print them.
//   - else, print the first language in the text.
// Please note that English texts are not used as default anymore!
//
// This version is based on original multilang filter by Gaetan Frenoy,
// rewritten by Eloy and skodak.
//
// Following new syntax is not compatible with old one:
//   <span lang="XX" class="multilang">one lang</span><span lang="YY" class="multilang">another language</span>

function multilang_filter($courseid, $text) {
	global $CFG;

	// [pj] I don't know about you but I find this new implementation funny :P
	// [skodak] I was laughing while rewriting it ;-)
	// [nicolasconnault] Should support inverted attributes: <span class="multilang" lang="en"> (Doesn't work curently)
	// [skodak] it supports it now, though it is slower - any better idea? 

	if (empty($text) or is_numeric($text)) {
		return $text;
	}

	if (empty($CFG->filter_multilang_force_old) and !empty($CFG->filter_multilang_converted)) {
		// new syntax
		$search = '/(<span(\s+lang="[a-zA-Z0-9_-]+"|\s+class="multilang"){2}\s*>.*?<\/span>)(\s*<span(\s+lang="[a-zA-Z0-9_-]+"|\s+class="multilang"){2}\s*>.*?<\/span>)+/is';
	} else {
		// old syntax
		$search = '/(<(?:lang|span) lang="[a-zA-Z0-9_-]*".*?>.*?<\/(?:lang|span)>)(\s*<(?:lang|span) lang="[a-zA-Z0-9_-]*".*?>.*?<\/(?:lang|span)>)+/is';
	}

	$result = preg_replace_callback($search, 'multilang_filter_impl', $text);

	if (is_null($result)) {
		return $text; //error during regex processing (too many nested spans?)
	} else {
		return $result;
	}
}

function multilang_filter_impl($langblock) {
	global $CFG;

	$mylang = str_replace('_utf8', '', current_language());
	static $parentcache;
	if (!isset($parentcache)) {
		$parentcache = array();
	}
	if (!array_key_exists($mylang, $parentcache)) {
		$parentlang = str_replace('_utf8', '', get_string('parentlanguage'));
		$parentcache[$mylang] = $parentlang;
	} else {
		$parentlang = $parentcache[$mylang];
	}

	$searchtosplit = '/<(?:lang|span)[^>]+lang="([a-zA-Z0-9_-]+)"[^>]*>(.*?)<\/(?:lang|span)>/is';

	if (!preg_match_all($searchtosplit, $langblock[0], $rawlanglist)) {
		//skip malformed blocks
		return $langblock[0];
	}

	$langlist = array();
	foreach ($rawlanglist[1] as $index=>$lang) {
		$lang = str_replace('_utf8', '', str_replace('-','_',strtolower($lang))); // normalize languages
		$langlist[$lang] = $rawlanglist[2][$index];
	}

	if (array_key_exists($mylang, $langlist)) {
		return $langlist[$mylang];
	} else if (array_key_exists($parentlang, $langlist)) {
		return $langlist[$parentlang];
	} else {
		$first = array_shift($langlist);
		return $first;
	}
}

?>
